Corresponding author: William Santana (
Academic editor: S. De Grave
Three new species and a new genus of majoid crabs from deep waters in the eastern Pacific are described and illustrated using morphological and molecular data. A new species of inachoidid,
Colavite J, Windsor A, Santana W (2019) Three new species and a new genus of majoid crabs from the eastern Pacific (
The Southeast Pacific Biological Oceanographic Project (
The amphi-American inachoididae
The second new species described herein belongs to the epialtid
A new genus,
Holotype and paratype specimens were deposited in the National Museum of Natural History, Smithsonian Institution, Washington, DC, USA (
Total genomic DNA was extracted from muscle tissue using either the Qiagen DNeasy Blood and Tissue extraction kit or an Omega Bio-tek EZNA Tissue DNA Kit. Partial sequences of the 12S, 16S, and barcode region of COI mitochondrial genes were amplified with the following primers respectively: 12SF (
Sequences generated for this study were combined with those from
Multiple sequence alignment was performed using the MAFFT FFT-NS-I (
All three mitochondrial loci (12S, 16S, COI) were successfully amplified and sequenced for the three new species. Nodes where maximum likelihood bootstrap support and Bayesian posterior probabilities greater than 50/0.5 are shown on the maximum likelihood phylogram (Fig.
Molecular phylogenetic tree represented as maximum likelihood topology of three mitochondrial and two nuclear genes (12S, 16S, COI, 18S, H3) to place
Peru, off Paita, Piura, Southeast Pacific Biological Oceanographic Project (
Peru, off Paita, Piura Southeast Pacific Biological Oceanographic Project (
Peru, west of Paita, Piura, 04°57'S to
Carapace pyriform, granulose, particularly on cardiac, branchial and intestinal regions. Second antennal article ventrolateral surface with strong, unarmed longitudinal keel. Third maxillipeds granulated; ischium and carpus with dense granulation, propodus smooth. First pleonal segment with a short spine or distinctly strong tubercle with several small tubercles around.
Carapace pyriform, longer than wide; dorsal surface covered by tubercles of different sizes (more prominent in females), particularly on cardiac, branchial and intestinal regions; gastric and branchial regions covered with hooked setae. Gastric, branchial, cardiac, intestinal regions with small tubercles. Gastric, hepatic, branchial, cardiac, intestinal regions clearly delimited laterally by grooves. Metagastric region with mesial prominent tubercle; gastric region with few small tubercles; mesocardiac region with four tubercles in line longitudinally, distal tubercles more prominent. Groove between cardiac and intestinal region smooth or with a few small tubercles in males and females. Hepatic, branchial, intestinal regions densely covered with sub-equal tubercles. Metabranchial region slightly depressed. Thoracic pleurites V–VIII gymnopleura not fused to one another, usually densely covered with small hooked setae.
Rostrum simple, short, slightly curved upwards. Supraorbital spine absent; orbital margin unarmed dorsally. Postorbital spine longer than the ocular peduncle, directed laterally and upwards around eyes. Antennular fossae longitudinally ovate; anteroventral margin unarmed. Interantennular septum longer than epistomial spine, compressed laterally, forming ventrally-directed keel. Antenna (flagellum included) distinctly exceeding rostral length. First and second antennal articles fused to epistome. Second article protruding anterolaterally; ventrolateral surface with strong longitudinal keel, unarmed; ventrolateral margin dentate, teeth acute. Third antennal article massive; fourth longest, cylindrical; fifth article smaller.
Epistome markedly wider than long. Epistomial spine separated by small gap from interantennular septum. Mouthfield sub-rectangular. Pterygostomial region subtriangular, smooth near mouth frame, densely tuberculated laterally, tubercles sub-equal. Sub-hepatic region strongly swollen, delimited from pterygostome by distinct slope, densely covered with sub-equal tubercles, several long setae.
Third maxillipeds almost completely covering buccal frame, ischia leaving distinct gap. Exopod long, nearly reaching distal margin of merus; granulated; lateral margin with strong lobe in proximal third. Ischium distinctly longer than broad, dorsal face with longitudinal, smooth, deep groove; with granules; mesial margin slightly convex; crista dentata with small, rounded, irregularly sized teeth. Merus slightly longer than half of ischium, granulated. Anterior margin deeply incised, anterolateral and anteromedial margins expanded, mesial margin with a row of setae. Palp cylindrical, slightly overreaching ischiomeral suture. Carpus granulated; propodus and dactylus smooth, fringed with row of long setae.
Thoracic sternites II–IV broadly triangular in males, with sparse hooked setae, small tubercles medially. Anterior half of sternites I–IV strongly sloping down laterally, forming prominent triangle medially; fourth sternite densely tuberculated, with smaller projection ventrally directed in males. Male sternites IV–VII covered with distinct, large tubercles, outside sterno-pleonal cavity; smooth in females.
Male and female chelipeds sub-cylindrical, homochelous, robust in males, slender in females. Dactylus (movable) and fixed finger approximately same length as palm in males and females, covered with sparse setae. Males with finger cutting edges with small teeth, sub-equal in distal half, leaving distinct proximal depressed gap in sub-proximal edge of dactylus. Distal two-thirds of finger cutting edges with sub-equal teeth in females. Male propodus conspicuously inflated, with sparse setae, small tubercles in dorsal margin, fewer tubercles in ventral margin. Propodus slender, smooth in females. Carpus setose, with several tubercles dorsally, unarmed in females. Merus with two rows of small tubercles in dorsal and mesoventral faces, row of strong tubercles in lateral face, with long setae. Ischium sparsely tuberculate, setose.
Male pleonal somites I–V free, sixth fused to telson. Pleotelson sub-triangular, rounded distally. Female pleonal somites I–IV free, somites V, VI, telson fused; pleotelson markedly arched, transversally oval. Male and female first pleonal somite with short spine or strong tubercle with several tubercles surrounding. Male somite I densely tubercular; somite VI-telson with scattered tubercles in the anterior margin. Female somites II–IV tubercular laterally; somites V–VI, telson evenly, densely tubercular in mesolateral region.
Northwest of Peru, from 04°57'S to
The specific epithet is derived from the Greek adjective
Although the phylogenetic analyses of seven of the 15 described species of
Morphological characters that can distinguish
Carapace densely covered with several long and short spines and acute tubercles. Rostrum bifurcated, proximally contiguous, becoming moderately divergent distally. Preorbital angles prolonged into long spines; postorbital margin cup-shaped, with small medial spine on anterior margin protecting eyes when retracted. Fissure between antennal basal article and postorbital margin closed. Basal article of antenna elongated with two strong spines in outer margin. Exopod of third maxilliped with small process in dorsal face extending into posterolateral margin of merus; ventral margin with strong spine in distal third; ischium dorsal face with longitudinal, smooth, deep “L” shaped groove.
Ecuador, off Machala, near Isla Santa Clara, Southeast Pacific Biological Oceanographic Project (
Ecuador, off Machala, near Isla Santa Clara,
Carapace pyriform, very spinulose, with one small spine on each side of the contiguous portion of the rostrum; one long, acute supraorbital spine; hepatic region with two long, distinct spines. Merus of
Carapace pyriform, longer than wide, with seven long lateral spines, eight spines in medial line; covered with sparsely distributed tufts of hooked setae, mainly in rostral, branchial regions. Carapace spines: base of rostrum with five spines, two between the orbits; two protogastric; six mesogastric; six metagastric; one urogastric; two long lateral, two smaller mesial hepatic. Branchial region with small sparse tubercles and short spines: eight protobranchial, with few interspaced tubercles; mesobranchial with six long lateral, four small mesial spines, few tubercles; three marginal metabranchial with acute tubercles interspaced; seven cardiac; two intestinal spines. Branchiostegal region with row of acute, strong spines along anterior-inferior half of molt line. Gastric, branchial, cardiac, intestinal regions delimited laterally by shallow grooves.
Rostrum long, bifurcated for distal 1/3 of entire length, divergent. Supraorbital spine long, acute; orbital margin with one small spine. Postorbital margin cup-shaped completely protecting eyes when retracted, with small medial spine on anterior margin. Basal article of antenna narrow, second article long with one long anterolateral spine aligned with supraorbital spine, one smaller posterolateral spine protecting eyestalk from below, one smaller spine below orbital fissure. Antenna almost exceeding rostral length (flagellum broken in holotype). Antennal article longest; third, fourth antennal articles thick, cylindrical; visible dorsally. Antennular fossae longitudinally ovate, longer than wider; posteroventral margin with one small projection. Interantennular septum long, compressed laterally, forming ventrally-directed keel.
Epistome narrower, more depressed than antennular fossae; posterior margin crenulate, antennal gland open in epistome with one tubercle at same level, another on mouthfield border. Endostome with two prominent, obliquely longitudinal endostomial ridges, completely closed.
Buccal field sub-rectangular, longer than wide, posterior edge narrower, with crenulated anterolateral angles with one strong acute spine on anterolateral margins. Pterygostomial region sub-triangular with four acute spines on lateral margin, 3–4 sub-equal tubercles; sub-hepatic region delimited from pterygostome by distinct slope.
Third maxillipeds completely covering buccal frame. Exopod long, nearly reaching distal margin of merus; dorsal face with one small process extending into posterolateral margin of merus; ventral margin with strong spine in distal third. Ischium distinctly longer than broad, dorsal face with longitudinal, smooth, deep “L” shaped groove; crista dentata with small, rounded, irregular sized teeth. Merus slightly longer than half of ischium, anteromesial border partially covering propodus; anterior margin deeply incised, anterolateral margins slightly expanded. Palp cylindrical, slightly overreaching ischiomeral suture. Carpus, propodus, dactylus smooth; propodus, with long distomesial setae, dactylus fringed with row of long setae.
Juvenile female thoracic sternites I–IV fused, broadly triangular, smooth, dense, covered by closely adhered pubescence. Anterior half of fused sternites I–IV sloping down in ventral view. Sterno-pleonal cavity completely closed by telson. Female sternites V–VII smooth; Margin of episternites IV–VII smooth.
Juvenile female pleonal somites I–VI, telson free, slightly raised medially forming low longitudinal ridge. One small spine in first somite; somites II–VI smooth. Telson triangular. Juvenile female holotype with a sealed pleon.
Juvenile female chelipeds subequal, long; ischium unarmed; merus armed with seven strong dorsal spines, row of six laterodistal tubercles, sparse tubercles present; carpus with sparse tubercles; propodus smooth; dactylus and fixed finger distinctly shorter than palm, slender, cutting edges with subequal teeth, tip incurving down.
Only known from the type-locality in Ecuador, near Isla Santa Clara,
The specific epithet
Carapace distinctly sub-circular in outline, dorsal surface prominently vaulted, particularly swollen at branchial regions. Urogastric region compressed by metabranchial lobes into a deep furrow. Four spines along dorsal midline of carapace: mesogastric, metagastric, cardiac, and intestinal. Branchiostegal region with two rows of small acute spines along molt line. Thoracic pleurites V–VII gymnopleura. Postorbital spine long, curved beyond eyes. Eyes not retractable. Endostomial ridge with two obliquely longitudinal, very curved prominences. Sterno-pleonal cavity longer than pleon plus telson, leaving gap between distal end of telson and its anterior margin. Gonopod reaching far beyond thoracic sternal suture IV/V, rather straight proximally and medially, distinctly curved inwards sub-distally, convergent anteriorly, apical plate curved down with three distinct lobes laterally.
The genus name is an arbitrary noun formed by the combination of the Latin
Peru, off Paita, Piura, Southeast Pacific Biological Oceanographic Project (
Peru, off Paita, Piura, Southeast Pacific Biological Oceanographic Project (
Ecuador, Gulf of Guayaquil, northwest of Tumbes, Southeast Pacific Biological Oceanographic Project (
Peru, off Paita, Piura, 05°01'S to
Same as for the genus.
Carapace distinctly sub-circular in outline, surface prominently inflated, particularly swollen at protogastric and branchial regions. Urogastric region compressed by metabranchial lobes into a deep furrow. Four spines - mesogastric, metagastric, cardiac, intestinal – along dorsal carapace midline. Dorsal carapace sparsely covered with long simple and hooked setae. Gastric region with two lateral spines, one protogastric, one mesogastric. One hepatic, one small sub-hepatic spines. Branchial region with four protobranchial spines; mesobranchial with four long, five shorter spines; two metabranchial, one lateral, one mesial spine above metabranchial lobe. Mesial border of branchial region with one distinct spine near the furrow, one cardiac and one intestinal spine. Branchiostegal region with two rows of spines, superior row with five strong, acute spines along most of posteroinferior half of molt line, at least five smaller spines in lower row. Gastric region delimited by shallow grooves; branchial, cardiac, intestinal regions delimited by well-marked grooves. Gastric, branchial regions with few tubercles or small spines. Pterygostomial region sub-triangular with five acute spines, few tubercles on lateral margin, smooth medially, inflated, visible in dorsal view. Thoracic pleurites V–VII gymnopleura.
Rostrum bifurcated, short, straight, more divergent in juveniles. Supraorbital spine acute, pointed forward. Postorbital spine long, curved beyond eyes. Eyes not retractable. Basal article of antenna narrow, second article long with two spines, one anterolateral, one posterolateral; one small sub-orbital spine in line with antennal gland. Antennae exceeding the rostral length, visible dorsally, flagellum short, thin; third antennal article longest; third and fourth antennal articles thick, cylindrical. Antennular fossae longitudinally ovate, longer than wide; interantennular septum long compressed laterally, forming ventrally-directed keel.
Epistome narrower than antennular fossae, anterior margin smooth, posterior margin crenulated; antennal gland open in epistome. Endostome with two obliquely prominent, longitudinal, very curved endostomial ridges. Buccal field sub-rectangular, longer than wide, narrower at posterior edge with smooth anterolateral angles.
Third maxillipeds covering buccal frame posteriorly, incompletely covering in anterior margin. Exopod long, nearly reaching distal margin of merus; ventral face with small process extending to posterolateral margin of merus. Ischium distinctly longer than broad, dorsal face smooth, deeply sculpted; crista dentata with very small, rounded teeth. Merus slightly longer than half of ischium, anteromesial border partially covering the propodus; anterior margin deeply incised, anterolateral margins slightly expanded, rounded. Palp cylindrical, slightly overreaching ischiomeral suture. Carpus, propodus and dactylus smooth; Propodus short, dactylus long and thin, with row of long setae on the distal margin. Male chelipeds equal, long, strong; merus, carpus and propodus sculpted by distinct sulcus in lateral and mesial faces; ischium smooth; merus armed with four dorsal spines, two smaller ventral spines; carpus with 3–4 blunt tubercles; propodus smooth; dactylus and fixed finger smooth, with same size as palm, cutting edges with sub-equal teeth in distal half, distinct proximal tooth in larger males; juvenile males and females fingers without gap.
Male thoracic sternite I-IV fused, broadly triangular, smooth; posterior half strongly sloping down in ventral view, forming a carina along lateral margin of telson. Sterno-pleonal cavity longer than telson, leaving gap between telson and anterior margin. Male sternites V–VII smooth; sternite VIII extending laterally beyond sterno-pleonal cavity, visible in ventral view. Margin of male episternites IV–VII smooth; female episternites IV–VII smooth, densely covered with small pubescence.
Male pleonal somites I–VI, telson free, smooth, slightly raised medially forming a low longitudinal ridge; first somite with distinct spine. Female pleonal somites I–IV, telson free; pleon markedly arched covering entire sterno-pleonal cavity; second somite with a distinct tubercle, sometimes forming a spine. Telson sub-triangular, terminating in rounded apex in males; female telson transversely oval.
First gonopod longer than thoracic sternal suture IV-V, straight proximally and medially, distinctly curved inwards sub-distally, convergent anteriorly; apical plate curved down with three well-pronounced lobes. Mesial lobe small, densely spinulate, curving toward sternal margin; distal lobe bilobed, long, tip rounded upwards; lateral lobe shorter than distal lobe, curved upward.
Ecuador, from Tumbes to Peru, Isla Lobos de Tierra at depths between 13 to 311 m.
The specific epithet
We are grateful to Rafael Lemaitre and Karen Reed (
Taxa included in the molecular phylogenetic analyses to place the newly described taxa within the context of the superfamily
phylogenetic data